We just found one of our 4-month-old RIR's under the roost, not moving. She is smaller than the rest of the girls and we have been a bit worried about her because of that, but she's had no other issues other than size until today. She is barely moving. Her skin is red, and when we isolated her inside in a smaller pen she just fell right over onto her face. What could it be? Is the sort of the "runt" of the litter and doomed to pass? Did the others starve her because of her size? Help!